FYI, we noticed the following commit (built with gcc-7): commit: aa6830997649d2c31ef86dc657d7e1799309824d ("exec: separate thread_count for files_struct") https://git.kernel.org/cgit/linux/kernel/git/jlayton/linux.git locks-execve in testcase: mdadm-selftests with following parameters: disk: 1HDD test_prefix: 10 on test machine: qemu-system-x86_64 -enable-kvm -cpu host -smp 2 -m 4G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +-------------------------------------------------------------------------------+-----------+------------+ | | v4.19-rc1 | aa68309976 | +-------------------------------------------------------------------------------+-----------+------------+ | boot_successes | 730 | 7 | | boot_failures | 191 | 96 | | WARNING:at#for_ip_interrupt_entry/0x | 21 | | | cpu_clock_throttled | 8 | | | WARNING:stack_recursion | 111 | | | WARNING:at#for_ip_swapgs_restore_regs_and_return_to_usermode/0x | 94 | | | Kernel_panic-not_syncing:VFS:Unable_to_mount_root_fs_on_unknown-block(#,#) | 4 | | | WARNING:at_ip__slab_free/0x | 2 | | | WARNING:at_ip_ip_finish_output2/0x | 1 | | | WARNING:at_ip_fsnotify/0x | 11 | | | WARNING:at_ip_do_sys_poll/0x | 3 | | | page_allocation_failure:order:#,mode:#(GFP_KERNEL|__GFP_COMP),nodemask=(null) | 1 | | | Mem-Info | 11 | | | WARNING:at_ip___perf_sw_event/0x | 1 | | | WARNING:at_ip_io_submit_one/0x | 1 | | | WARNING:at_ip__mutex_lock/0x | 1 | | | WARNING:at_ip___sys_sendmsg/0x | 1 | | | BUG:sleeping_function_called_from_invalid_context_at_mm/memory.c | 48 | | | BUG:scheduling_while_atomic | 48 | | | WARNING:at_lib/usercopy.c:#_copy_to_user | 48 | | | RIP:_copy_to_user | 48 | | | BUG:sleeping_function_called_from_invalid_context_at_mm/slab.h | 17 | | | BUG:sleeping_function_called_from_invalid_context_at_kernel/locking/rwsem.c | 16 | | | invoked_oom-killer:gfp_mask=0x | 9 | | | Out_of_memory:Kill_process | 8 | | | WARNING:at_net/sched/sch_generic.c:#dev_watchdog | 2 | | | RIP:dev_watchdog | 2 | | | End_of_test:RCU_HOTPLUG | 3 | | | WARNING:at_net/mac80211/tx.c:#__ieee80211_csa_update_counter[mac80211] | 3 | | | RIP:__ieee80211_csa_update_counter[mac80211] | 3 | | | RIP:_raw_spin_unlock_irqrestore | 1 | | | RIP:console_unlock | 2 | | | WARNING:at_fs/file.c:#put_files_struct | 0 | 96 | | RIP:put_files_struct | 0 | 96 | +-------------------------------------------------------------------------------+-----------+------------+ [ 537.421851] WARNING: CPU: 1 PID: 3465 at fs/file.c:419 put_files_struct+0xd2/0xe0 [ 537.445766] Modules linked in: multipath loop raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid10 raid1 raid0 sr_mod cdrom sg ppdev ata_generic pata_acpi snd_pcm snd_timer crc32c_intel snd soundcore pcspkr serio_raw ata_piix libata i2c_piix4 floppy parport_pc parport ip_tables [ 537.508909] CPU: 1 PID: 3465 Comm: mdmon Not tainted 4.19.0-rc1-00001-gaa68309 #1 [ 537.522003] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 537.538662] RIP: 0010:put_files_struct+0xd2/0xe0 [ 537.547145] Code: 48 8d 45 28 49 39 c7 74 08 4c 89 ff e8 57 f3 ff ff 5b 48 89 ee 48 8b 3d ac b4 cd 01 5d 41 5c 41 5d 41 5e 41 5f e9 ee ff fa ff <0f> 0b eb d2 66 2e 0f 1f 84 00 00 00 00 00 66 66 66 66 90 41 55 41 [ 537.576711] RSP: 0018:ffffc90002777ce8 EFLAGS: 00010202 [ 537.586268] RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffff8800792b53d8 [ 537.598828] RDX: 0000000000000040 RSI: 0000000000000186 RDI: ffffffff822ef144 [ 537.610816] RBP: ffff8800792b5340 R08: 0000000000000001 R09: 0000000000022640 [ 537.622716] R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000 [ 537.634248] R13: 0000000000000001 R14: 0000000000000040 R15: ffff8800792b5368 [ 537.646011] FS: 00007f719e64b700(0000) GS:ffff88013fd00000(0000) knlGS:0000000000000000 [ 537.661759] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 537.672780] CR2: 00007f212a84a5b0 CR3: 000000000260a001 CR4: 00000000000206e0 [ 537.687914] Call Trace: [ 537.696175] do_exit+0x2eb/0xbc0 [ 537.705516] ? __switch_to_asm+0x40/0x70 [ 537.714499] ? __switch_to_asm+0x40/0x70 [ 537.722399] ? __switch_to_asm+0x34/0x70 [ 537.730925] do_group_exit+0x3a/0xa0 [ 537.738803] get_signal+0x2ad/0x630 [ 537.747170] do_signal+0x36/0x650 [ 537.754599] ? do_nanosleep+0xdb/0x1c0 [ 537.762827] exit_to_usermode_loop+0x71/0xe0 [ 537.772154] do_syscall_64+0x16c/0x180 [ 537.779964] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 537.791337] RIP: 0033:0x7f719dd2928d [ 537.799541] Code: Bad RIP value. [ 537.806633] RSP: 002b:00007ffffd9497e0 EFLAGS: 00000293 ORIG_RAX: 0000000000000023 [ 537.824313] RAX: fffffffffffffdfc RBX: 0000000000000000 RCX: 00007f719dd2928d [ 537.846194] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffffd9497f0 [ 537.858490] RBP: 00007ffffd949840 R08: 0000000000000002 R09: 0000000000000000 [ 537.871059] R10: 00007ffffd949760 R11: 0000000000000293 R12: 000055d6405b9da0 [ 537.884786] R13: 00007ffffd949cb0 R14: 0000000000000000 R15: 0000000000000000 [ 537.896779] ---[ end trace c89f1ccb1fa11d49 ]--- To reproduce: git clone https://github.com/intel/lkp-tests.git cd lkp-tests find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz bin/lkp qemu -k -m modules.cgz job-script # job-script is attached in this email Thanks, Rong Chen